Trench-brace.



No. 891,897. PATENTED .TUNE 30, 1908.

G. P. ASTROM. TRENGH BRAGE.

APPLICATION FILED AUG.7,1906.

CARL P. ASTROM, OF ORANGE, NEW JERSEY.

TRE NCH-BRACE Specification of Letters Patent.

Patented June 30, 1908.

Application filed August 7, 1906. -Serial No. 329,582.

T o all whom it may concern:

Be it known thatI, CARL I. AsTRoM, a citizen of the United States to the extent of vhaving duly taken the .necessary steps required by law to declare my intentionof becoming such citizen, and a resident of Orange, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Trench-Braces, of which the following is a specification.

My present improvement relates to braces useful in a number of connections among which is its application to trench braces; in other words, to braces used in excavations to prevent the shoring timbers from collapsing inward.

The accompanyingI drawings show one form which my invention may take in a trench brace. I do not limit myself, however, to this particular form, but mean to include all others within the scope of my invention as claimed.

Infth'e drawings Figure 1 shows my improved trench brace in elevation. Figs. 2 and 3 are sectional views of the same, the

' sections being taken atright angles to each in elevation.

other and some of the parts being shown Figs. 4' and 5 are detailed sectional views at right angles to each other showing one shoe ofJ the brace with end of bolt-broken away. These views show how the shoe and boltconstitute a universal joint, and how at the same time it is impossible for the bolt to twist or turn about its axis in the shoe; Fig.'6 is a top elevation of one of the shoes with the bolt shank in section as same appears when looked at in the direction of the arrow from a section through the line 6-6 in Fig. 1.

Describing now my improved trench brace as shown, said brace com rises two shoes 1, the bottom of each of w 'ch abuts against timbers on opposite sides of the trench to be shored. To prevent the shoes from twisting when the brace is tightened up, spikes or sharp corners 9 are preferably provided on the bottoms of the shoes.

j The shoes 1 consist referably of castings shank of the bolt to project through it as shown.

The heads 3 of the bolts are rounded on the top to form bearing surfaces for them against the bottom of the cavities in the shoes. These portions of the shoes are likewise rounded as follows: In the iirst place it will be noted that the cavity in the shoes is longer in one direction than the other. The

long direction will hereafter be designated the longitudinal direction of the shoe or cavity, and is in the direction of the line B-B in Fig. 6, while the short direction will hereinafter be designated the transverse direction of the shoe or cavity, and is in the direction of the line A-A of the same ligure.

The head 3 of the bolt is proportioned to the transverse direction of the cavity so that it is impossiblefor the head of the bolt to turner twist within the cavity. Inother words the sidesof the cavity in a transverse direction abut more or less closely against the sides of the headI of the b'olt (see Fig. 5). Coming back now to -the description of the curved bearingsurfaces for the bolt head in the bottom of the cavity in each shoe,it will be seen from an ins ection ofvFigs. 4 and 5, that in a longitudine. direction the bottom of the cavity is concavely formed Whereas in a transverse direction the bottom of the cavity is convexly formed (Fig. 5). These in connection with the curvature ofthe bolthead and the action of the shank of the bolt Within the elongated opening 12 in the top of the shoe constitutes an easy working universal joint of great stren ,th the arrangement and operation of whic i will now be described.

Referrin to Fig. 4 it will be noted that here the bo t can rock longitudinally relative to the shoe or vice versa the shoe can rock in the same direction relative to the bolt. In doing this the head of the bolt slides lengthwise of the cavity in the shoe; in other words it bears on or follows the concave curvature of the shoe bottom. Furthermore it will be noted that this motion of the bolt-head is approximately circular, pivoting about the imaginary center C (Fig. 4) due to the fact that the sides of the short diameter of the elongated opening 12 at the 4 top of the shoe more or less snugly confine the bolt shank (see Figs. 4 and 6).

In Fig. 5 it is shown how the shoe and bolt can swing relatively'to each other in the opposite direction of that in Fig. 4 5 in other acter of the joints between the bolts and shoe, it will now be necessary to complete the description of the brace, to state that one of the bolts, namely 2, is threaded as shown, and of such size as to telescope Within the tube 5. The other bolt need not be threaded. It is secured by its shank to the other end of the. same tube 5 ermanently by the 6. A nut 7 is provi ed on the threaded o t 2.

The action of the device described will now be clear.

When the brace is in place as shown in Fig. 1, to brace the timbers apart it is only necessary to use a Wrench on the nut 7 to force the threaded bolt and its sleeve or tube 5 in op ositeV directions outwardly and thereby drive the shoes against the timbers to be shored. The universal character of the joints between the bolt-heads and the shoes, takes u any twist or getting out of plumb of the timbers, while the snug fitting of the bolt-heads within'the shoe cavities 1n their transverse direction, prevents turning of said bolts in the shoes which would otherwise take place when the nut 7 is tightened up to operate the brace. g

Having thus described my invention, what I claim is:

1. In combination, a shoe in which the bottom of its cavity is concavely curvedin its longitudinal direction and convexly curved in its transverse direction,-and in which there is an elongated opening in its top, the long diameter of which is located in the transverse direction ol" the shoe-cavity;

and a bolt rojecting out of said opening with its head in the shoe-cavity; sai hea being free to slide longitudinally on the bottom of the shoe and being confined transversely by the sides ofthe shoe-cavity to prevent rotation of the bolt-head within the s oe.

2. In a trench brace the combination of two pairs of members, each pair of which com rises a shoe and a bolt,--the shoe having t e bottom of its cavity concavely curved in its longitudinaldirection and convexly curved in its transverse` direction and also having an elongated openin in its top, the long diameter. of which is Iocated in the transverse direction of the shoe-cavity,-the bolt projecting out of said opening with its head in the shoe-cavity said head being free to slide longitudinally on the bottom of the shoe and being confined transversely by the `sides of the shoe-cavity to revent rotation.

of the bolt -head within t e shoe; screw threads on one of said bolts; a sleeve secured to the other of said bolts and ada ted to telescope over the shank of the t readed bolt; and a nut cooperating with the thread on said last named bolt. y

3. In a trench brace, the combination of a lengthwise adjustable connecting-member having a shoe at each end, the shoe having a face in contact with the end of the connecting-member, said face being concave in one direction and convex in a dlrection at rightangles to the former, the shoe and connectlngmember being adapted to each other to have sliding contact between the end of said connecting-member and the concave portion of the shoe, and rolling contact with its convex portion.

In witness whereof, I have signed my name to the foregoing speciiication in the presence of two subscribing witnesses.

` CARL P. ASTROM. Witnesses:

MOLLY4 M'. MULLIGAN, EUGENE E. SPIEGELBERG. 

